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<TITLE>Switch -OI[-][:&lt;minsize&gt;] - save identical files as references</TITLE>
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<P class="title">Switch <B>-OI[-][:&lt;minsize&gt;]</B> -
save identical files as references<hr></P>

<p>If this switch is specified, WinRAR analyzes the file contents before
starting archiving. If several identical files are found, the first file
in the set is saved as usual file and all following files are saved as
references to this first file. It allows to reduce the archive size,
but applies some restrictions to resulting archive. You must not delete
or rename the first identical file in archive after the archive was created,
because it will make extraction of following files using it as a reference
impossible. If you modify the first file, following files will also have
the modified contents after extracting.</p>

<p>While typically it is possible to unpack a reference without unpacking
the first file, in some cases it might be necessary to involve the first file
into extraction to create following files successfully. Such cases include
a multivolume archive stored on several removable media and archives
containing a very large number of references.</p>

<p>It is recommended to use -oi only if you compress a lot of identical
files and will not modify an archive later. If all identical files are
small enough to fit into compression dictionary specified with
<A HREF="HELPSwMD.htm">-md&lt;size&gt;</A> switch, <A HREF="HELPSwS.htm">-s</A>
can provide more flexible solution than -oi.</p>

<p>Optional &lt;minsize&gt; value allows to define the minimum file size
threshold. Files smaller than &lt;minsize&gt; are not analyzed
and not considered as identical. If this parameter is not
present, it is assumed to be 64 KB by default. Selecting
too small &lt;minsize&gt; may increase the time required to detect
identical files.</p>

<p>Supported for <a href="HELPRAR5Format.htm">RAR 5.0</a> archives only.</p>

<p>Use -oi- if you wish to disable identical file processing enabled
in WinRAR configuration.</p>

<p>This switch is the command line equivalent of
<a href="HELPGetArcOptions.htm#ident">Save identical files as references</a>
option in "Archive name and parameters" dialog.</p>

<h1><B>Example</B></h1>

<p>Save contents of current folder to archive.rar.
Store identical files, larger than or equal to 1000000 bytes,
as references.</p>

<p class="sample">WinRAR a -oi:1000000 archive</p>

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